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73-634: Damüls is known for its abundance of snow . In 2006, Damüls was awarded the honorary title "the snowiest village in the world". Damüls is situated at an altitude of 1,430 m. It has an area of 20.92 km². It borders on the Bregenz Forest , the Biosphere Reserve Großes Walsertal , the Laternsertal, and all other Vorarlberg districts ( Bludenz , Feldkirch and Dornbirn ). The most famous mountain peak in

146-457: A microscope from 1885 onward by Wilson Alwyn Bentley found the wide variety of snowflakes we know about today. Ukichiro Nakaya developed a crystal morphology diagram, relating crystal shape to the temperature and moisture conditions under which they formed, which is summarized in the following table: below saturation above saturation Dendrites Hollow prisms Needles Solid plates Dendrites Solid plates Prisms The shape of

219-401: A rainband ), when temperature is near freezing at the surface. The strong convection that develops has enough moisture to produce whiteout conditions at places which the line passes over as the wind causes intense blowing snow. This type of snowsquall generally lasts less than 30 minutes at any point along its path, but the motion of the line can cover large distances. Frontal squalls may form

292-433: A cirque (corrie or cwm), a typically armchair-shaped geological feature, which collects snow and where the snowpack compacts under the weight of successive layers of accumulating snow, forming névé. Further crushing of the individual snow crystals and reduction of entrapped air in the snow turns it into glacial ice. This glacial ice will fill the cirque until it overflows through a geological weakness or an escape route, such as

365-649: A crystal morphology diagram, relating crystal shapes to the temperature and moisture conditions under which they formed, which is summarized in the following table. Dendrites Hollow prisms Needles Solid plates Dendrites Solid plates Prisms Nakaya discovered that the shape is also a function of whether the prevalent moisture is above or below saturation. Forms below the saturation line tend more toward solid and compact while crystals formed in supersaturated air tend more toward lacy, delicate, and ornate. Many more complex growth patterns also form, which include side-planes, bullet-rosettes, and planar types, depending on

438-447: A droplet has frozen, it grows in the supersaturated environment—one where air is saturated with respect to ice when the temperature is below the freezing point. The droplet then grows by diffusion of water molecules in the air (vapor) onto the ice crystal surface where they are collected. Because water droplets are so much more numerous than the ice crystals, the crystals are able to grow to hundreds of micrometers or millimeters in size at

511-589: A few molecules in the droplet need to get together by chance to form an arrangement similar to that in an ice lattice. The droplet freezes around this "nucleus". In warmer clouds, an aerosol particle or "ice nucleus" must be present in (or in contact with) the droplet to act as a nucleus. Ice nuclei are very rare compared to cloud condensation nuclei on which liquid droplets form. Clays, desert dust, and biological particles can be nuclei. Artificial nuclei include particles of silver iodide and dry ice , and these are used to stimulate precipitation in cloud seeding . Once

584-568: A hemisphere's fall , winter, and spring, the atmosphere over continents can be cold enough through the depth of the troposphere to cause snowfall. In the Northern Hemisphere, the northern side of the low-pressure area produces the most snow. For the southern mid-latitudes , the side of a cyclone that produces the most snow is the southern side. A cold front , the leading edge of a cooler mass of air, can produce frontal snowsqualls —an intense frontal convective line (similar to

657-485: A highly porous, sintered material made up of a continuous ice structure and a continuously connected pore space, forming together the snow microstructure". Almost always near its melting temperature, a snowpack is continually transforming these properties wherein all three phases of water may coexist, including liquid water partially filling the pore space. After deposition, snow progresses on one of two paths that determine its fate, either by ablation (mostly by melting) from

730-435: A minimum extent of 2 million square kilometres (0.77 × 10 ^  sq mi) each August to a maximum extent of 45 million square kilometres (17 × 10 ^  sq mi) each January or nearly half of the land surface in that hemisphere. A study of Northern Hemisphere snow cover extent for the period 1972–2006 suggests a reduction of 0.5 million square kilometres (0.19 × 10 ^  sq mi) over

803-530: A mountain range results in adiabatic cooling, and ultimately condensation and precipitation. Moisture is gradually removed from the air by this process, leaving drier and warmer air on the descending, or leeward , side. The resulting enhanced snowfall, along with the decrease in temperature with elevation, combine to increase snow depth and seasonal persistence of snowpack in snow-prone areas. Mountain waves have also been found to help enhance precipitation amounts downwind of mountain ranges by enhancing

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876-488: A series of snow events, punctuated by freezing and thawing, over areas that are cold enough to retain snow seasonally or perennially. Major snow-prone areas include the Arctic and Antarctic , the Northern Hemisphere, and alpine regions. The liquid equivalent of snowfall may be evaluated using a snow gauge or with a standard rain gauge , adjusted for winter by removal of a funnel and inner cylinder. Both types of gauges melt

949-409: A short distance ahead of the surface cold front or behind the cold front where there may be a deepening low-pressure system or a series of trough lines which act similar to a traditional cold frontal passage. In situations where squalls develop post-frontally, it is not unusual to have two or three linear squall bands pass in rapid succession separated only by 25 miles (40 kilometers), with each passing

1022-419: A snow fall or seasonal snowpack, or by transitioning from firn (multi-year snow) into glacier ice . Over the course of time, a snowpack may settle under its own weight until its density is approximately 30% of water. Increases in density above this initial compression occur primarily by melting and refreezing, caused by temperatures above freezing or by direct solar radiation. In colder climates, snow lies on

1095-449: A snowflake is determined primarily by the temperature and humidity at which it is formed. Freezing air down to −3 °C (27 °F) promotes planar crystals (thin and flat). In colder air down to −8 °C (18 °F), the crystals form as hollow columns, prisms or needles. In air as cold as −22 °C (−8 °F), shapes become plate-like again, often with branched or dendritic features. At temperatures below −22 °C (−8 °F),

1168-478: A snowflake on the mountain symbol. A stylized snowflake has been part of the emblem of the 1968 Winter Olympics , 1972 Winter Olympics , 1984 Winter Olympics , 1988 Winter Olympics , 1998 Winter Olympics and 2002 Winter Olympics . A six pointed stylized hexagonal snowflake used for the Order of Canada (a national honor system) has come to symbolize Canadians ' northern heritage and diversity. In heraldry,

1241-608: A snowpack can create flow fingers and ponding or flow along capillary barriers, which can refreeze into horizontal and vertical solid ice formations within the snowpack. Among the measurements of the properties of snowpacks that the International Classification for Seasonal Snow on the Ground includes are: snow height, snow water equivalent, snow strength, and extent of snow cover. Each has a designation with code and detailed description. The classification extends

1314-416: A snowslide or snowslip) is a rapid flow of snow down a sloping surface. Avalanches are typically triggered in a starting zone from a mechanical failure in the snowpack (slab avalanche) when the forces on the snow exceed its strength but sometimes only with gradually widening (loose snow avalanche). After initiation, avalanches usually accelerate rapidly and grow in mass and volume as they entrain more snow. If

1387-630: A substance denser than névé , yet less dense and hard than glacial ice . Firn resembles caked sugar and is very resistant to shovelling. Its density generally ranges from 550 to 830 kilograms per cubic metre (34 to 52 lb/cu ft), and it can often be found underneath the snow that accumulates at the head of a glacier . The minimum altitude that firn accumulates on a glacier is called the firn limit , firn line or snowline . There are four main mechanisms for movement of deposited snow: drifting of unsintered snow, avalanches of accumulated snow on steep slopes, snowmelt during thaw conditions, and

1460-593: A tiny particle in supersaturated air masses by attracting supercooled cloud water droplets, which freeze and accrete in crystal form. Complex shapes emerge as the flake moves through differing temperature and humidity zones in the atmosphere, such that individual snowflakes differ in detail from one another, but may be categorized in eight broad classifications and at least 80 individual variants. The main constituent shapes for ice crystals, from which combinations may occur, are needle, column, plate, and rime. Snow appears white in color despite being made of clear ice. This

1533-470: A variety of shapes, basic among these are platelets, needles, columns and rime . As snow accumulates into a snowpack , it may blow into drifts. Over time, accumulated snow metamorphoses, by sintering , sublimation and freeze-thaw . Where the climate is cold enough for year-to-year accumulation, a glacier may form. Otherwise, snow typically melts seasonally, causing runoff into streams and rivers and recharging groundwater . Major snow-prone areas include

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1606-550: A very cold temperature inversion present. Snow clouds usually occur in the context of larger weather systems, the most important of which is the low-pressure area, which typically incorporate warm and cold fronts as part of their circulation. Two additional and locally productive sources of snow are lake-effect (also sea-effect) storms and elevation effects, especially in mountains. Mid-latitude cyclones are low-pressure areas which are capable of producing anything from cloudiness and mild snow storms to heavy blizzards . During

1679-424: A water droplet has frozen as an ice nucleus, it grows in a supersaturated environment—wherein liquid moisture coexists with ice beyond its equilibrium point at temperatures below freezing. The droplet then grows by deposition of water molecules in the air (vapor) onto the ice crystal surface where they are collected. Because water droplets are so much more numerous than the ice crystals due to their sheer abundance,

1752-472: Is "the transformation that the snow undergoes in the period from deposition to either melting or passage to glacial ice". Starting as a powdery deposition, snow becomes more granular when it begins to compact under its own weight, be blown by the wind, sinter particles together and commence the cycle of melting and refreezing. Water vapor plays a role as it deposits ice crystals, known as hoar frost , during cold, still conditions. During this transition, snow "is

1825-442: Is due to diffuse reflection of the whole spectrum of light by the small crystal facets of the snowflakes. Snowflakes nucleate around mineral or organic particles in moisture-saturated, subfreezing air masses. They grow by net accretion to the incipient crystals in hexagonal formations. The cohesive forces are primarily electrostatic. In warmer clouds, an aerosol particle or "ice nucleus" must be present in (or in contact with)

1898-635: Is free. The Church of St. Nikolaus occupies a prominent place in the mountain village of Damüls. The art-historically valuable church with its preserved frescoes depicting a Bible for the poor dates from the time of the arrival of the Walsers in the 13th/14th centuries. In the region, many old traditions are still alive and well, including the typical dialect that is still spoken here. Wearing traditional folk costumes (" tracht ") on festive occasions also contributes to an authentic yesteryear atmosphere. Alpine Transhumance , or mobile mountain meadow culture,

1971-429: Is not a requirement, as blowing snow can create a ground blizzard . Snowstorm intensity may be categorized by visibility and depth of accumulation. Snowfall's intensity is determined by visibility , as follows: Snowsqualls may deposit snow in bands that extend from bodies of water as lake-event weather or result from the passage of an upper-level front. The International Classification for Seasonal Snow on

2044-584: Is one of the prime factors preserving the natural and cultural landscape of the region, along with the strong tradition of cheese production in Vorarlberg. In 2011, the UNESCO declared the "Dreistufenwirtschaft" in the Bregenz Forest to be an intangible cultural heritage. Thanks to the merging of the two ski areas of Damüls and Mellau in 2010, the largest ski area in the Bregenz Forest, and one of

2117-462: Is quite popular to make paper snowflakes by folding a piece of paper several times, cutting out a pattern with scissors and then unfolding it. The Book of Isaiah refers to the atonement of sins causing them to appear "white as snow" before God (cf. Isaiah 1:18 ); Snowflakes are also often used as symbols representing winter or cold conditions. For example, snow tires which enhance traction during harsh winter driving conditions are labelled with

2190-524: Is still practiced in Damüls. This means that farmers bring their cattle to wherever food is available in the mountains. Depending on the season, cattle will change stables several times a year. Alpine transhumance is also called "Dreistufenwirtschaft" (literally "three stage economy") in German because the mountain pastures are managed in three stages: lower, middle, and upper mountain altitudes. This transhumance

2263-464: Is termed ocean-effect or bay-effect snow . The effect is enhanced when the moving air mass is uplifted by the orographic influence of higher elevations on the downwind shores. This uplifting can produce narrow but very intense bands of precipitation which may deposit at a rate of many inches of snow each hour, often resulting in a large amount of total snowfall. The areas affected by lake-effect snow are called snowbelts . These include areas east of

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2336-616: The Christmas season , especially in Europe and North America. As a Christian celebration, Christmas celebrates the incarnation of Jesus , who according to Christian belief atones for the sins of humanity; so, in European and North American Christmas traditions, snowflakes symbolize purity. Snowflakes are also traditionally associated with the " White Christmas " weather that often occurs during Christmastide. During this period, it

2409-645: The Great Lakes , the west coasts of northern Japan, the Kamchatka Peninsula in Russia, and areas near the Great Salt Lake , Black Sea , Caspian Sea , Baltic Sea , and parts of the northern Atlantic Ocean. Orographic or relief snowfall is created when moist air is forced up the windward side of mountain ranges by a large-scale wind flow. The lifting of moist air up the side of

2482-411: The movement of glaciers after snow has persisted for multiple years and metamorphosed into glacier ice. When powdery snow drifts with the wind from the location where it originally fell, forming deposits with a depth of several meters in isolated locations. After attaching to hillsides, blown snow can evolve into a snow slab, which is an avalanche hazard on steep slopes. An avalanche (also called

2555-808: The polar regions , the northernmost half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture and cold temperatures. In the Southern Hemisphere , snow is confined primarily to mountainous areas, apart from Antarctica . Snow affects such human activities as transportation : creating the need for keeping roadways, wings, and windows clear; agriculture : providing water to crops and safeguarding livestock; sports such as skiing , snowboarding , and snowmachine travel; and warfare . Snow affects ecosystems , as well, by providing an insulating layer during winter under which plants and animals are able to survive

2628-704: The snowflake is a stylized charge . Three different snowflake symbols are encoded in Unicode : "snowflake" at U+2744 (❄); "tight trifoliate snowflake" at U+2745 (❅); and "heavy chevron snowflake" at U+2746 (❆). In the Tang Dynasty, snowflakes in poetry sometimes served as a symbol of the cosmic energy of the Tao and the Milky Way galaxy . A selection of photographs taken by Wilson Bentley (1865–1931): Comprehensive photographic studies of fresh snowflakes show

2701-648: The 35-year period. The following are world records regarding snowfall and snowflakes: The cities (more than 100,000 inhabitants) with the highest annual snowfall are Aomori (792 cm), Sapporo (485 cm) and Toyama (363 cm) in Japan , followed by St. John's (332 cm) and Quebec City (315 cm) in Canada , and Syracuse, NY (325 cm). According to the International Association of Cryospheric Sciences, snow metamorphism

2774-460: The Ground defines "height of new snow" as the depth of freshly fallen snow, in centimeters as measured with a ruler, that accumulated on a snowboard during an observation period of 24 hours, or other observation interval. After the measurement, the snow is cleared from the board and the board is placed flush with the snow surface to provide an accurate measurement at the end of the next interval. Melting, compacting, blowing and drifting contribute to

2847-413: The accumulated snow and report the amount of water collected. At some automatic weather stations an ultrasonic snow depth sensor may be used to augment the precipitation gauge. Snow flurry , snow shower , snow storm and blizzard describe snow events of progressively greater duration and intensity. A blizzard is a weather condition involving snow and has varying definitions in different parts of

2920-758: The area, a popular hiking destination from Damüls, is the Damülser Mittagsspitze (2,095 m). In the late Middle Ages c. 1300, the Walser ethnic folk group fled from the Swiss Kanton Wallis to this area seeking a better way of life and agricultural land. They were allowed to settle in Vorarlberg (then largely under the Swabian Counts of Mountfort ), in the west of Tyrol and in Graubünden . From 1313 onwards, Damüls

2993-475: The atmosphere due to their mass, and may collide and stick together in clusters, or aggregates. These aggregates are usually the type of ice particle that falls to the ground. Guinness World Records lists the world's largest aggregated snowflakes as those of January 1887 at Fort Keogh , Montana , which were claimed to be 15 inches (38 cm) wide—well outside the normally documented range of aggregated flakes of three or four inches in width. Single crystals

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3066-458: The avalanche moves fast enough some of the snow may mix with the air forming a powder snow avalanche, which is a type of gravity current . They occur in three major mechanisms: Many rivers originating in mountainous or high-latitude regions receive a significant portion of their flow from snowmelt. This often makes the river's flow highly seasonal resulting in periodic flooding during the spring months and at least in dry mountainous regions like

3139-454: The changing temperature and humidity within the atmosphere that the snowflake falls through on its way to the ground. Snowflakes that look identical, but may vary at the molecular level, have been grown under controlled conditions. Although snowflakes are never perfectly symmetrical, the growth of a non-aggregated snowflake often approximates six-fold radial symmetry , arising from the hexagonal crystalline structure of ice. At that stage,

3212-462: The cold. Snow develops in clouds that themselves are part of a larger weather system. The physics of snow crystal development in clouds results from a complex set of variables that include moisture content and temperatures. The resulting shapes of the falling and fallen crystals can be classified into a number of basic shapes and combinations thereof. Occasionally, some plate-like, dendritic and stellar-shaped snowflakes can form under clear sky with

3285-448: The conditions and ice nuclei. If a crystal has started forming in a column growth regime at around −5 °C (23 °F) and then falls into the warmer plate-like regime, plate or dendritic crystals sprout at the end of the column, producing so called "capped columns". Magono and Lee devised a classification of freshly formed snow crystals that includes 80 distinct shapes. They documented each with micrographs. Snow accumulates from

3358-410: The conditions and ice nuclei. If a crystal has started forming in a column growth regime, at around −5 °C (23 °F), and then falls into the warmer plate-like regime, then plate or dendritic crystals sprout at the end of the column, producing so called "capped columns". Magono and Lee devised a classification of freshly formed snow crystals that includes 80 distinct shapes. They are listed in

3431-544: The contribution of snowmelt to river hydraulics and ground hydrology . In doing so, they employ a variety of instruments to observe and measure the phenomena studied. Their findings contribute to knowledge applied by engineers , who adapt vehicles and structures to snow, by agronomists , who address the availability of snowmelt to agriculture , and those, who design equipment for sporting activities on snow. Scientists develop and others employ snow classification systems that describe its physical properties at scales ranging from

3504-450: The crystal facets and hollows/imperfections mean that the crystals often appear white in color due to diffuse reflection of the whole spectrum of light by the small ice particles. Micrography of thousands of snowflakes from 1885 onward, starting with Wilson Alwyn Bentley , revealed the wide diversity of snowflakes within a classifiable set of patterns. Closely matching snow crystals have been observed. Ukichiro Nakaya developed

3577-479: The crystals are able to grow to hundreds of micrometers or millimeters in size at the expense of the water droplets. This process is known as the Wegener–Bergeron–Findeisen process . The corresponding depletion of water vapor causes the droplets to evaporate, meaning that the ice crystals grow at the droplets' expense. These large crystals are an efficient source of precipitation, since they fall through

3650-465: The crystals become plate-like or columnar, depending on the degree of saturation. As Nakaya discovered, shape is also a function of whether the prevalent moisture is above or below saturation. Forms below the saturation line trend more towards solid and compact. Crystals formed in supersaturated air trend more towards lacy, delicate and ornate. Many more complex growth patterns also form such as side-planes, bullet-rosettes and also planar types depending on

3723-446: The difficulty of measuring snowfall. Glaciers with their permanent snowpacks cover about 10% of the earth's surface, while seasonal snow covers about nine percent, mostly in the Northern Hemisphere, where seasonal snow covers about 40 million square kilometres (15 × 10 ^  sq mi), according to a 1987 estimate. A 2007 estimate of snow cover over the Northern Hemisphere suggested that, on average, snow cover ranges from

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3796-572: The droplet to act as a nucleus. The particles that make ice nuclei are very rare compared to nuclei upon which liquid cloud droplets form; however, it is not understood what makes them efficient. Clays, desert dust, and biological particles may be effective, although to what extent is unclear. Artificial nuclei include particles of silver iodide and dry ice , and these are used to stimulate precipitation in cloud seeding . Experiments show that "homogeneous" nucleation of cloud droplets only occurs at temperatures lower than −35 °C (−31 °F). Once

3869-415: The expense of the water droplets by the Wegener–Bergeron–Findeisen process . These large crystals are an efficient source of precipitation, since they fall through the atmosphere due to their mass, and may collide and stick together in clusters, or aggregates. These aggregates are snowflakes , and are usually the type of ice particle that falls to the ground. Although the ice is clear, scattering of light by

3942-446: The following main categories (with symbol): They documented each with micrographs. The International Classification for Seasonal Snow on the Ground describes snow crystal classification, once it is deposited on the ground, that include grain shape and grain size. The system also characterizes the snowpack, as the individual crystals metamorphize and coalesce. The snowflake is often a traditional seasonal image or motif used around

4015-442: The gap between two mountains. When the mass of snow and ice is sufficiently thick, it begins to move due to a combination of surface slope, gravity and pressure. On steeper slopes, this can occur with as little as 15 m (49 ft) of snow-ice. Scientists study snow at a wide variety of scales that include the physics of chemical bonds and clouds ; the distribution, accumulation, metamorphosis, and ablation of snowpacks; and

4088-453: The ground all winter. By late spring, snow densities typically reach a maximum of 50% of water. Snow that persists into summer evolves into névé , granular snow, which has been partially melted, refrozen and compacted. Névé has a minimum density of 500 kilograms per cubic metre (31 lb/cu ft), which is roughly half of the density of liquid water. Firn is snow that has persisted for multiple years and has been recrystallized into

4161-448: The ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide or sublimate away. Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets, which freeze in hexagonal-shaped crystals. Snowflakes take on

4234-442: The ideal six-fold symmetric shape. Very occasionally twelve branched snowflakes are observed; they maintain the six-fold symmetry. Snowflakes form in a wide variety of intricate shapes, leading to the notion that "no two are alike". Although nearly-identical snowflakes have been made in laboratory, they are very unlikely to be found in nature. Initial attempts to find identical snowflakes by photographing thousands of them with

4307-445: The individual crystal to the aggregated snowpack. A sub-specialty is avalanches , which are of concern to engineers and outdoors sports people, alike. Snow science addresses how snow forms, its distribution, and processes affecting how snowpacks change over time. Scientists improve storm forecasting, study global snow cover and its effect on climate, glaciers, and water supplies around the world. The study includes physical properties of

4380-466: The largest ski regions in the state of Vorarlberg, was created: the ski area Damüls-Mellau . There is a 2.5 km long natural toboggan run which is illuminated two days a week. This resort region is known for its abundance of snow. In 2006, Damüls was awarded the title "Snowiest village in the world". On average, there is 9.30 meters of fresh snow per season. Numerous hiking trails lead from Damüls over alpine meadows and to summits with views over

4453-615: The lift needed for condensation and precipitation. A snowflake consists of roughly 10 water molecules which are added to its core at different rates and in different patterns depending on the changing temperature and humidity within the atmosphere that the snowflake falls through on its way to the ground. As a result, snowflakes differ from each other though they follow similar patterns. Snow crystals form when tiny supercooled cloud droplets (about 10  μm in diameter) freeze . These droplets are able to remain liquid at temperatures lower than −18 °C (0 °F), because to freeze,

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4526-563: The material as it changes, bulk properties of in-place snow packs, and the aggregate properties of regions with snow cover. In doing so, they employ on-the-ground physical measurement techniques to establish ground truth and remote sensing techniques to develop understanding of snow-related processes over large areas. In the field snow scientists often excavate a snow pit within which to make basic measurements and observations. Observations can describe features caused by wind, water percolation, or snow unloading from trees. Water percolation into

4599-502: The mountain West of the US or most of Iran and Afghanistan , very low flow for the rest of the year. In contrast, if much of the melt is from glaciated or nearly glaciated areas, the melt continues through the warm season, with peak flows occurring in mid to late summer. Glaciers form where the accumulation of snow and ice exceeds ablation. The area in which an alpine glacier forms is called

4672-504: The prior classifications of Nakaya and his successors to related types of precipitation and are quoted in the following table: All are formed in cloud, except for rime, which forms on objects exposed to supercooled moisture. Snowflake A snowflake is a single ice crystal that has achieved a sufficient size, and may have amalgamated with others, which falls through the Earth's atmosphere as snow . Each flake nucleates around

4745-401: The same point roughly 30 minutes apart. In cases where there is a large amount of vertical growth and mixing, the squall may develop embedded cumulonimbus clouds resulting in lightning and thunder which is dubbed thundersnow . A warm front can produce snow for a period as warm, moist air overrides below-freezing air and creates precipitation at the boundary. Often, snow transitions to rain in

4818-416: The size of a dime (17.91 mm in diameter) have been observed. Snowflakes encapsulated in rime form balls known as graupel . Although ice by itself is clear, snow usually appears white in color due to diffuse reflection of the whole spectrum of light by the scattering of light by the small crystal facets of the snowflakes of which it is comprised. The shape of the snowflake is determined broadly by

4891-417: The snowflake has the shape of a minute hexagon. The six "arms" of the snowflake, or dendrites, then grow independently from each of the corners of the hexagon, while either side of each arm grows independently. The microenvironment in which the snowflake grows changes dynamically as the snowflake falls through the cloud and tiny changes in temperature and humidity affect the way in which water molecules attach to

4964-467: The snowflake. Since the micro-environment (and its changes) are very nearly identical around the snowflake, each arm tends to grow in nearly the same way. However, being in the same micro-environment does not guarantee that each arm grows the same; indeed, for some crystal forms it does not because the underlying crystal growth mechanism also affects how fast each surface region of a crystal grows. Empirical studies suggest less than 0.1% of snowflakes exhibit

5037-421: The surrounding mountain tops. The temperatures are pleasant even during hot periods in midsummer. Snow Snow comprises individual ice crystals that grow while suspended in the atmosphere —usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions,

5110-482: The temperature and humidity at which it is formed. Rarely, at a temperature of around −2 °C (28 °F), snowflakes can form in threefold symmetry — triangular snowflakes. Most snow particles are irregular in form, despite their common depiction as symmetrical. It is unlikely that any two snowflakes are alike due to the estimated 10 (10 quintillion) water molecules which make up a typical snowflake, which grow at different rates and in different patterns depending on

5183-406: The warm sector behind the front. Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water, warming the lower layer of air which picks up water vapor from the lake, rises up through the colder air above, freezes, and is deposited on the leeward (downwind) shores. The same effect occurring over bodies of salt water

5256-551: The world. In the United States , a blizzard occurs when two conditions are met for a period of three hours or more: a sustained wind or frequent gusts to 35 miles per hour (16 m/s), and sufficient snow in the air to reduce visibility to less than 0.4 kilometers (0.25 mi). In Canada and the United Kingdom , the criteria are similar. While heavy snowfall often occurs during blizzard conditions, falling snow

5329-554: Was populated by Walsers. At the time, the Supreme Court (Damüls and Fontanella ) was independent. The inhabitants of Damüls, in return, joined the Montfort House to serve with "spear and shield" in the event of war. The Vorarlberger FIS Skimuseum Damüls offers exhibitions on the long history of skiing in Vorarlberg. In addition to historic and rare Alpine skis, ski jump-related objects are also on display. The entry

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